TRACERS From Description to Quantification Monika Rhein IUP

TRACERS: From Description to Quantification Monika Rhein, IUP Bremen, Germany C. Böning, J. Bullister, J. Dengg, S. Doney, M. England, R. Fine, T. Haines, S. Khatiwala, D. Kieke, O. Klatt, B. Klein, D. Le. Bel, J. Lupton, P. Robbins, W. Roether, B. Smethie, D. Smythe-Wright, R. Steinfeldt, R. Well 1

Formation of Deep and Bottom Water A New Deep Water Mass in Drake Passage Ventilation of the Pacific Tracer ages: what do they tell us? Conclusion / Outlook 2

AABW is formed : western Weddell Sea, western and eastern Ross Sea, Adelie Coast, Amery Ice Shelf 3

CFC-11 along 0°E, 1984 - 1998 2 deep CFC cores in AABW Klatt, Roether, Hoppema, Bulsie wicz, Fleischmann, Rodehacke, Fahrbach, Weiss, Bullister, JGR, 107, 2002 4

Estimates of AABW Production Rates WSBW from DWBC transports WSBW from tracer budgets : 2 -5 Sv : 3 -5 Sv AABW from shelf water budgets : 5 -15 Sv AABW from PO 4* and C-14 : 15 Sv Orsi, Johnson, Bullister, 1999, Prog. Oceanogr. 43 55 -109 5

AABW - Formation Rate from CFC Inventory CFC-inventory [million moles] Atlantic : 6. 2 (1987) Ind. +Pac. : 4. 8 (1993) Orsi, Johnson, Bullister, 1999, Prog. Oceanogr. 43 55 -109 6

Calculation of AABW formation by Orsi et al. all AABW formation regions treated similar: -- volume of water sinking across 2500 m isobath: V -- entrainment of ambient water while sinking -- CFC- Saturation of this mix: 35% (from obs. ) CFC Inventory = V • • 0. 35 • C(t) dt + Loss Atlantic : 4. 9 Sv 60% Indian + Pacific : 3. 2 Sv 40% TOTAL: 8. 1 -9. 4 Sv Orsi, Johnson, Bullister, 1999 7

AABW Formation and CFCs in Ocean Climate Model Transient tracers to assess skill of NCAR model CFC- Inventory. , AABW 106 moles obs. contr. -------------------Atlantic 1987 6. 2 1. 0 Ind+Pac 1993 4. 8 0. 6 Sensitivity studies: A) BBL: Beckmann and Döscher, 1997 B) High_sal: restore S to Smax on shelf and adjacent to it Doney and Hecht, JPO 32, 2002 8

Am Ad RS WS model with BBL CFC WS: Weddell Sea RS: Ross Sea Ad: Adelie Coast Am: Amery Ice Shelf Pt, BBL-Levitus CFC inventory: Atl. 1. 0 (obs. 6. 2) I+P 0. 7 (obs. 4. 8) S, BBL-Levitus sig 2 BBL-Levitus Doney and Hecht, 2002 0° 90° 180° 270° 0° 9

High_sal: restore S to Smax on shelf improved AABWformation CFC-inventory: Atl. 3. 4 (obs 6. 2) I+P 1. 4 (obs 4. 8) Am Ad RS WS CFC p. T, mod-Lev. S, mod-Lev Doney and Hecht, 2002 0° 90° 180° 10 270° 0°

Detection of a new water mass in Drake Passage He-3 across Drake Passage 1990 He-anomaly at 2 = 36. 95 Ant SAm 1999 11 Well, Roether, Stevens DSR , subm.

SPDSW Southeast Pacific Deep Slope Water Well, Roether, Stevens, 2002 Lupton, Pyle, Well, Jenkins, Schlosser, Top, 2002 12

With OMP analysis: Fraction SPDSW in % SPDSW Drake Passage: 7 Sv (l. ADCP, CTD) Well, Roether, Stevens ANT SA 13

Formation rates of NADW using CFCs CFC-inventory LSW 1997: 16. 6 million moles formation rate: 4. 4 -5. 6 Sv low NAO : 1. 8 - 2. 4 Sv high NAO: 8. 1 -10. 8 Sv Rhein, Fischer, Smethie, Smythe-Wright, Weiss, Mertens, Min, Fleischmann, 14 Putzka, JPO, 2002

CFC - inventories and formation rates of NADW components 1991 -inventory formation rate million mole Sv u. LSW 4. 2 2. 2 c. LSW 14. 7 7. 4 ISOW 5. 0 5. 2 DSOW 5. 9 2. 4 --------------------------total 29. 8 17. 2 Sv Smethie and Fine, DSRI, 2001 15

CFC - inventories and formation rates of NADW components 1997 c. LSW layer CFC-11 inventory 1997 inventory form. rate million mole Sv u. LSW 7. 4 2. 6 c. LSW 20. 5 7. 9 ISOW 10. 0 7. 7 DSOW 8. 7 2. 4 ----------------total 46. 6 20. 6 Le. Bel, Smethie, Andrie, Bullister, Jones, Min, Rhein, Roether, Smythe-Wright, Weiss 2002 16

Modeling CFC inventories and LSW formation rates CFC observation 1/3° FLAME model formation rate by volume change : 4. 3 Sv rate from CFC inv: 3. 5 -4. 4 Sv a) CFC-11 model Böning, Rhein, Dengg, Dorow, GRL 2003, accepted b) 17

Ventilation of the Pacific from Tracer Ages CFC-11 along 135°W, 1993 1400 m 30°S 50°N Fine, Maillet, Sullivan, Wiley, JGR, 182001

CFC-inventory , 1993, full water column Bullister, Sonnerup, Fine, Min, Mecking, Smethie, Warner, Weiss, 2002 19

CFC ages on isopycnals SSM 26. 2 STUW 25. 0 A B NPIW SAMW 26. 8 AAIW 27. 2 C D 20 Fine, Maillet, Sullivan, Wiley, JGR, 2001

NPIW SAMW Bullister et al. , 2002 21

Ventilation flux [Sv] : Volume / mean tracer age Total Wind driven Thermohaline circ. < 26. 5< <27. 3 -------------------------------NP 111 Sv 50% SP 123 Sv 35% 65% subtrop. gyre subpolar gyre NP 41 Sv 9 Sv SP 25 Sv agree Sverdrup theory 17 Sv 22 Fine, Maillet, Sullivan, Wiley, JGR, 2001

Ventilation and Mixing of Indian Ocean Waters Full water column inventory in 1995: 100 million moles Fine, Smethie, Bullister, Min, Warner, Rhein, Weiss, DSR, revised, 2002 23 Poster

Age : time elapsed since last at the surface -- boundary conditions in source region -- Mixing : ages are not conservative 24

Thermocline ventilation in subtropical North Pacific dc/dt = -v • dc/dy +K • d²c/dy² d /dt = -v • d /dy +K • d² /dy² +1 10°N NEC diffusion 20°N advection, diffusion model with CFCs ideal age tracer 40°N subp. gyre outcrop diffusion 25 Sonnerup, Quay, Bullister, DSR I, 1999

<15 -25 years : agree with CFC ages within 25% older : tracer ages considerably younger CFC-11 ages younger than CFC-12 difference increase with age CFC-11, 12 ages older than ratio ages Sonnerup, 2001, GRL 28, 1739 -1742 26

Relationship between the ideal age and the tracer age C(r, t)= Co(t-t‘) G(r, t‘)dt‘ Co(t) : conc. at surface G(r, t): age spectrum Holzer and Hall, 2000 G(r, t) dt: mass fraction of fluid at r that was at the surface at time interval t -- t+dt 1 st temporal moment: mean age 2 nd temp. moment: width of the age spectrum 27 Waugh, Hall, Haine, JGR, 2002, subm.

Testing in a GCM mean age tracer age ideal age a) 300 m b) 1000 m c) 1500 m Khatiwala, Visbeck, Schlosser, DSR I, 2001 28

after 200 years integration: mean Labrador Sea (1500 m) 3. 3 Subtrop. subduction (500 m) 15. 8 Western Boundary (1500 m) 38. 4 ³H-³He 3. 9 12. 8 35. 8 ideal 4. 0 21. 7 56. 7 -- tracer ages younger than ideal ages -- mean age sensitive to long transit time pathways although they make up only a small fraction 29 Khatiwala, Visbeck, Schlosser, 2001

use temporal change of ³H/³He ages to estimate mixing a) b) Robbins, Price, Owens, Jenkins, JPO 30, 2000 Isopycnals outcrop north Azores Current: southward penetration by lateral mixing across AC at 33°N c) 30

Relic CFC-11 age, Labrador Sea Water LSW estimates time scales of spreading for young component age in source region: 15 years 31 Fine, Rhein, Andrie, GRL, 2002, subm.

Future developments moored tracer sampler 32

Conclusions -- CFC inventories: AABW and NADW formation rates -- ³He signal: new water mass in Drake Passage -- CFC ages : Ventilation rates of upper and intermediate Pacific -- ³H/³He age : role of lateral mixing -- tracers to assess model skills -- tracer age - ideal age , age spectrum 33

WOCE Tracer: all sections (concentrations) isopycnal age distributions, North and South Atlantic: CFCs, ³He www. ocean. uni-bremen. de/en/projects/aims/tab. html. . /projects/aims/isoage. html. . /projects/aims_satl/qual. html 34